Gas filling ystem

ABSTRACT

To provide a gas filling system capable of optimizing filling of a gas tank depending on the cooling capability of a gas station. A gas filling system comprises: a vehicle having a gas tank; a gas station having a cooling device that cools a gas from a gas supply source, the gas station discharging the gas cooled by the cooling device to fill the gas tank with the gas, and a temperature sensor that detects the temperature of the gas cooled by the cooling device on the upstream side of the gas tank. The vehicle has a first controller that determines the filling flow rate of the gas to the gas tank based on the gas temperature detected by the temperature sensor.

TECHNICAL FIELD

The present invention relates to a gas filling system that fills a gastank mounted on a vehicle with a gas at a gas station.

BACKGROUND ART

A gas fuel vehicle having a gas tank, such as a fuel cell vehicle, stopsat a gas station to fill the gas tank with a fuel gas dispensed througha filling nozzle. As known, if the fuel gas is hydrogen gas, thetemperature rises as the tank is filled.

The hydrogen station described in Patent Document 1 comprises a storageunit that stores pressurized hydrogen gas, a dispenser that fills thegas tank with the hydrogen gas from the storage unit, and an absorptionchiller that cools the hydrogen gas. The absorption chiller previouslycools the hydrogen gas supplied to the storage unit and the dispenser,and the gas tank is filled with the previously cooled hydrogen gas.Thus, the filling time is reduced.

CITATION LIST Patent Document

Patent Document 1: Japanese Patent Laid-Open No. 2005-83567

SUMMARY OF INVENTION Technical Problem

However, when a plurality of fuel cell vehicles are successively filled,the chiller may be unable to adequately cool the hydrogen gas dependingon the cooling capability. If the gas tank is filled with theinadequately cooled hydrogen gas at the same flow rate as that of theadequately cooled hydrogen gas, the temperature in the gas tank may risebeyond the design temperature (85 degrees C., for example). In thisregard, the technique disclosed in Patent Document 1 does not take thecooling capability of the chiller into account and thus needs furtherimprovement.

In addition, the technique disclosed in Patent Document 1 does notconsider the way of determining the filling flow rate. Supposing thatthe hydrogen station determines the filling flow rate regardless of theconditions of the vehicle, the determined flow rate is not alwaysoptimum for the vehicle.

An object of the present invention is to provide a gas filling systemthat can optimally fill a gas tank depending on the cooling capabilityof a gas station.

Means for Solving the Problems

In order to attain the object, a gas filling system according to thepresent invention comprises: a vehicle having a gas tank; a gas stationhaving a cooling device that cools a gas from a gas supply source, thegas station discharging the gas cooled by the cooling device to fillsaid gas tank with the gas, a temperature sensor that detects thetemperature of the gas cooled by said cooling device on the upstreamside of said gas tank; and a first controller that determines thefilling flow rate of the gas to said gas tank based on the gastemperature detected by said temperature sensor. The first controller isprovided in said vehicle.

According to the present invention, the filling flow rate can be changeddepending on the temperature of the gas cooled by the cooling device,and therefore, filling can be optimally performed depending on thecooling capability of the cooling device. As a result, the gas tank canbe filled with a predetermined amount of gas (a full or specified amountof gas) in the shortest possible time while maintaining a stableinternal condition of the gas tank. In addition, since the firstcontroller in the vehicle determines the filling flow rate, it is alsopossible that an optimum filling flow rate reflecting conditions of thevehicle (characteristics of the gas tank, for example) is determined.

Preferably, said first controller may have a map of the filling flowrate for each gas temperature to be detected by said temperature sensorand may select the filling flow rate from the map based on the gastemperature detected by said temperature sensor. With thisconfiguration, the filling flow rate can be easily determined. Inparticular, the first controller of the vehicle can retain a mapproduced by taking into account the conditions of the vehicle(characteristics of the gas tank, for example), so that the map does notneed to be updated for each vehicle on the gas station side.

Preferably, said first controller may determine the filling flow ratebased on characteristics concerning said gas tank. With thisconfiguration, an optimum filling flow rate reflecting thecharacteristics concerning the gas tank can be determined. Here, thecharacteristics concerning the gas tank include characteristics of thegas tank and characteristics of influences exerted on the gas tank. Theformer characteristics primarily include the heat radiation performanceand the temperature rise rate. The latter characteristics include thecooling characteristics that vary depending on the position of the gastank in the vehicle, for example.

Preferably, said temperature sensor may detect said gas temperature atthe start of filling or during filling. According to the configuration,in the case where the gas temperature is detected at the start offilling, the cooling capability of the cooling device can be determinedat the start of filling. Meanwhile, in the case where the gastemperature is detected during filling, the presence or absence of anabnormality of the cooling device can be detected during filling. Inaddition, in the case where the gas temperature is detected duringfilling, the filling flow rate can be determined again during fillingdepending on the detected gas temperature.

According to a preferred aspect of the present invention, said vehiclemay have a first communication device connected to said firstcontroller. The gas station may have a flow rate controlling device; asecond communication device that receives information about saiddetermined filling flow rate from said first communication device; and asecond controller that controls said flow rate controlling device toachieve the filling flow rate received by said second communicationdevice. According to this configuration, the vehicle and the gas stationcan communicate with each other, so that the filling flow ratedetermined in the vehicle does not need to be manually input to the gasstation.

More preferably, said temperature sensor may detect the gas temperatureat said cooling device. With this configuration, filling can beoptimized based on the gas temperature at the cooling device, and thecooling capability of the cooling device and the presence or absence ofan abnormality of the cooling device can be suitably determined.

Preferably, at least one of said first controller and said secondcontroller may store a transmission/reception history between said firstcommunication device and said second communication device. Morepreferably, said transmission/reception history may include a history oftransmission of the information about said determined filling flow ratefrom said first communication device to said second communicationdevice. According to such configuration, for example, when the vehicleis inspected, whether or not filling has been performed at the optimumfilling flow rate reflecting the conditions of the vehicle can bechecked by checking the transmission/reception history.

Preferably, the gas filling system according to the present inventionmay further comprise a display device that provides an indication thatsaid filling flow rate is being controlled or has been controlled basedon the gas temperature detected by said temperature sensor. According tothis configuration, a person who performs filling can visually checkwhether filling is being or has been optimally performed according tothe cooling capability.

Preferably, said first controller may determine a lower filling flowrate when said temperature sensor detects a higher gas temperature thanwhen said temperature sensor detects a lower gas temperature. With thisconfiguration, for example, even when the gas temperature is high as aresult of successive fillings, the gas tank can be filled with apredetermined amount of gas in a short time while preventing thetemperature in the gas tank from reaching a design temperature. On theother hand, if the filling flow rate is raised when the gas temperatureis low, the gas tank can be filled with a predetermined amount of gas ina shorter time than in the case where the gas temperature is high.

Preferably, the gas filling system according to the present inventionmay further comprise a sensor that obtains information about theinterior of said gas tank, and said first controller may determine thefilling flow rate based on the information obtained by said sensor.According to this configuration, filling can be performed suitably forthe conditions in the gas tank to be filled. Furthermore, since theinformation about the interior of the gas tank is obtained by detection,the filling flow rate can be more precisely controlled than in the casewhere the information is obtained by estimation.

More preferably, said sensor may include at least one of a temperaturesensor and a pressure sensor. According to this configuration, forexample, when it is detected that the temperature in the gas tank is toohigh, the filling flow rate can be lowered to prevent further rise ofthe temperature in the gas tank.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing a gas filling system according toan embodiment;

FIG. 2 is a diagram showing a configuration of the gas filling systemaccording to the embodiment;

FIG. 3 is a flow chart for illustrating a filling process of the gasfilling system according to the embodiment; and

FIG. 4 is an example of a filling flow rate map used in the fillingprocess according to the embodiment.

EMBODIMENTS FOR CARRYING OUT THE INVENTION

In the following, a gas filling system according to a preferredembodiment of the present invention will be described with reference tothe accompanying drawings. In the example described below, the gasfilling system fills a fuel cell vehicle having a fuel cell system withhydrogen gas from a gas station. As well known, the fuel cell system hasa fuel cell that generates electric power by an electrochemical reactionbetween a fuel gas (hydrogen gas, for example) and an oxidation gas(air, for example), or the like.

As shown in FIG. 1, a gas filling system 1 comprises a hydrogen station2 serving as a gas station, and a fuel cell vehicle 3 to which hydrogengas is supplied from the hydrogen station 2, for example.

As shown in FIG. 2, the hydrogen station 2 has a curdle (gas supplysource) 11 that stores hydrogen gas, a filling nozzle 12 for ejectingthe hydrogen gas into a gas tank 30 mounted on the vehicle, and a gasflow channel 13 that connects the curdle 11 and the filling nozzle 12 toeach other. The filling nozzle 12 is a component referred to also as afilling coupling and is connected to a receptacle 32 of the vehicle 3when hydrogen gas filling is performed. The filling nozzle 12 and thereceptacle 32 form a connection unit that connects the hydrogen station2 and the gas tank 32 to each other.

The gas flow channel 13 includes, from the side of the curdle 11, acompressor 14 that compresses the hydrogen gas received from the curdle11 and discharges the compressed hydrogen gas, an accumulator 15 thatstores the hydrogen gas pressurized to a predetermined pressure by thecompressor 14, a flow rate control valve 16 that adjusts the flow rateof the hydrogen gas supplied from the accumulator 15, a flowmeter 17that measures the flow rate of the hydrogen gas, a pre-cooler 18 thatpreliminarily cools the hydrogen gas flowing in the gas flow channel 13,and a temperature sensor T that detects the temperature of the hydrogengas on the downstream side of the pre-cooler 18. The hydrogen station 2further has a communication device 21, a display device 22, an outsideair temperature sensor 23 and a controller 24, and various devices areelectrically connected to the controller 24. Although not shown, ashut-off valve that opens the gas flow channel 13 when filling isperformed is disposed on the accumulator 13 or on the downstream side ofthe accumulator 13.

The flow rate control valve 16 is an electrically driven valve, and thedriving source is a step motor, for example. The flow rate of thehydrogen gas is adjusted by changing the valve position of the flow ratecontrol valve 16 by means of the step motor in response to theinstruction from the controller 24. In this way, the filling flow rateof the hydrogen gas to the gas tank 30 is controlled. The flowmeter 17measures the controlled filling flow rate, and the controller 24feedback-controls the flow rate control valve 16 to achieve a desiredfilling flow rate based on the measurement. As an alternative, a flowrate controlling device other than the flow fate control valve 16 may beused.

The pre-cooler 18 cools the hydrogen gas from the accumulator 15 fromabout room temperature to a predetermined low temperature (−20 degreesC., for example) by heat exchange. The heat exchange in the pre-cooler18 may be any of indirect heat exchange, intermediate medium heatexchange and regenerative heat exchange, and the pre-cooler 18 can havea well-known structure. For example, the pre-cooler 18 has a pipethrough which hydrogen gas flows, and the pipe is housed in a containerin which a coolant flows to achieve heat exchange between the hydrogengas and the coolant. In this case, the temperature of the cooledhydrogen gas can be adjusted by adjusting the amount and temperature ofthe coolant supplied to the container. The temperature sensor T detectsthe temperature of the hydrogen gas cooled by the pre-cooler 18 in thisway, and the detection signal is input to the controller 24.

The communication device 21 has a communication interface to performradio communication, such as infrared communication. The display device22 displays various kinds of information, such as the filling flow rateduring filling, on a screen thereof. The display device 22 may have anoperation panel for selecting or specifying a desired filling amount orthe like on the display screen.

The controller 24 is constituted by a microcomputer incorporating a CPU,a ROM and a RAM. The CPU performs desired calculations according to acontrol program to perform various controlling and other processing. TheROM stores the control program and control data processed by the CPU,and the RAM is used mainly as working spaces for various controllingprocessing. The controller 24 is electrically connected not only to thecommunication device 21 and other devices shown by the alternate longand short dash lines in FIG. 2 but also to the curdle 11, the compressor14, the accumulator 15 and the pre-cooler 18 to comprehensively controlthe entire hydrogen station 2. The controller 24 controls thecommunication device 21 to transmit information available in thehydrogen station 2 to the vehicle 3.

The vehicle 3 has the gas tank 30 and the receptacle 32 described above.The gas tank 30 is a fuel gas supply source for a fuel cell and is ahigh-pressure tank capable of storing hydrogen gas at 35 MPa or 70 MPa,for example. The hydrogen gas in the gas tank 30 is supplied to the fuelcell through a supply pipe (not shown). The gas tank 30 is replenishedwith hydrogen gas from the hydrogen station 2 through the receptacle 32and a filling pipe 34. The filling pipe 34 includes a check valve 36 toprevent backflow of the hydrogen gas, for example. A temperature sensor40 and a pressure sensor 42 detect the temperature and pressure of thehydrogen gas in the gas tank 30, respectively, and can be provided onthe supply pipe or filling pipe 34.

The vehicle 3 further has a communication device 44 that transmits andreceives various kinds of information to and from the communicationdevice 21 of the hydrogen station 2, a controller 46 constituted by amicrocomputer as with the controller 24 of the hydrogen station 2, and adisplay device 48 that displays various kinds of information on ascreen. The communication device 44 is associated with the communicationdevice 21 and has a communication interface to perform radiocommunication, such as infrared communication. The communication device44 is incorporated in the receptacle 32 or fixed in a lid box of thevehicle 3 so that the communication device 44 can communicate with thecommunication device 21 with the filling nozzle 12 connected to thereceptacle 32. The controller 46 comprehensively controls the vehicle 3based on the detection results received from various sensors includingthe temperature sensor 40 and the pressure sensor 42. In addition, thecontroller 46 controls the communication device 44 to transmitinformation available in the vehicle 3 to the hydrogen station 2. Thedisplay device 48 may be a part of a car navigation system, for example.

In the gas filling system 1 described above, when the vehicle 3 isfilled with hydrogen gas, the filling nozzle 12 is first connected tothe receptacle 32. Then, the hydrogen station 2 is activated. Then, thehydrogen gas stored in the accumulator 15 is cooled by the pre-cooler 18and then discharged into the gas tank 30 through the filling nozzle 12to fill the gas tank 30.

The gas filling system 1 according to this embodiment controls thefilling flow rate by determining the filling flow rate in the vehicle 3and transmitting the data thereof to the hydrogen station 2.

Next, with reference to the flowchart of FIG. 3, determination andcontrol of the filling flow rate by the gas filling system 1 will bedescribed.

First, when a person who performs filling connects the filling nozzle 12to the receptacle 32 and performs a filling start operation to permitdischarge of hydrogen gas from the hydrogen station 2 to the gas tank30, filling is started (step S1). Then, the hydrogen gas stored in theaccumulator 15 is cooled by the pre-cooler 18 and then discharged intothe gas tank 30.

When filling is started, the tank pressure, the tank temperature and thepre-cooler temperature are read. The tank pressure is the pressure ofthe hydrogen gas in the gas tank 30 and is detected by the pressuresensor 42. The tank temperature is the temperature of the hydrogen gasin the gas tank 30 and is detected by the temperature sensor 40. Thedetection signals indicating the tank pressure and the tank temperatureare input to the controller 46. Thus, the controller 46 grasps the tankpressure and the tank temperature immediately after the start offilling. On the other hand, the pre-cooler temperature is thetemperature of the hydrogen gas in the pre-cooler 18 and is detected bythe temperature sensor T. The detection signal indicating the pre-coolertemperature is input to the controller 24, and the controller 24instructs the communication device 21 to transmit the detection value ofthe pre-cooler temperature to the communication device 44 in the vehicle3. In this way, the controller 46 in the vehicle 3 grasps the pre-coolertemperature immediately after the start of filling.

Once these three pieces of information are read, the controller 46selects or determines the filling flow rate based on a filling flow ratemap stored in the ROM or the like (step S2). FIG. 4 shows an example ofthe filling flow rate map. A filling flow rate map Ma is provided foreach of a plurality of pre-cooler temperatures (for example, T₁, T₂ andT₃ relate to each other according to T₁<T₂<T₃), and the column and therow in the table represent the tank pressure and the tank temperature,respectively. For example, if the detected pre-cooler temperature is T₁,the detected tank pressure is 40 MPa, and the detected tank temperatureis 0 degrees C., the controller 46 selects and determines D4 (m³/min) asthe filling flow rate.

Each filling flow rate in the filling flow rate map Ma is a filling flowrate at which the gas tank 30 can be smoothly and quickly filled withhydrogen gas under the condition determined by the tank pressure, thetank temperature and the pre-cooler temperature. More specifically, eachfilling flow rate in the filling flow rate map Ma is a flow rate atwhich the gas tank 30 can be filled with the highest possible amount(the full filling amount, for example) of hydrogen gas in the shortestpossible time under the condition determined by the three factorsdescribed above while preventing the temperature in the gas tank 30 fromreaching a predetermined upper limit (85 degrees C., for example) underthe above three conditions. Although the tank pressure increases inincrements of 10 MPa and the tank temperature increases in increments of10 degrees C. in the filling flow rate map Ma, these increments can bearbitrarily set, of course. Similarly, the filling flow rate maps can beprovided for any pre-cooler temperatures, such as every 2 to 3 degreesC., 5 degrees C. and 10 degrees C.

Here, two characteristics of the magnitude of the filling flow rate inthe filling flow rate maps Ma will be described.

First, for the same tank pressure and the same tank temperature, thefilling flow rate decreases as the pre-cooler temperature increases. Forexample, when the tank pressure is 40 MPa and the tank temperature is 0degrees C. the filling flow rate for the pre-cooler temperature T₂ islower than the filling flow rate D4 for the pre-cooler temperature T₁.By using the lower filling flow rate, the gas tank 30 can be filled inthe shortest possible time while preventing the temperature in the gastank 30 from reaching the upper limit even when the pre-coolertemperature rises because of successive fillings.

Second, for the same pre-cooler temperature, the filling flow rate canincrease as the tank pressure increases. In addition, for the samepre-cooler temperature, the filling flow rate can increase as the tanktemperature decreases. For example, for the pre-cooler temperature T₁,the filling flow rate H1 (for a tank pressure of 80 MPa and a tanktemperature of −30 degrees C.) is the highest of the filling flow ratesA1 to H8 in the filling flow rate map Ma, and the filling flow rate A8(for a tank pressure of 10 MPa and a tank temperature of 40 degrees C.)is the lowest. By using lower filling flow rates for lower tankpressures or higher tank temperatures in this way, the gas tank 30 canbe filled in the shortest possible time while preventing the temperaturein the gas tank 30 from reaching the upper limit.

Such filling flow rate map Ma is preferably based on characteristicsconcerning the gas tank 30 mounted in the vehicle 3.

More specifically, various types of gas tanks 30 have been developed,and those gas tanks have different heat radiation performances ortemperature rise rates depending on the material, the surface area, thestructure thereof or the like. For example, a gas tank 30 lined withaluminum has a higher heat radiation performance than a gas tank 30lined with resin (polyethylene or the like). In addition, the heatradiation performance of the gas tank 30 varies depending on thecharacteristics or composition of the resin used as the liner.Furthermore, the characteristics of cooling of the gas tank 30 by windor the like varies depending on the position of the gas tank 30 in thevehicle 3. Thus, the characteristics of the gas tank 30 and thecharacteristics of influences exerted on the gas tank 30 can vary forthe current or future vehicle 3.

Thus, according to a preferred aspect of this embodiment, the fillingflow rate map Ma stored in the controller 46 of the vehicle 3 take intoaccount the characteristics concerning the gas tank 30 mounted in thevehicle 3 described above. For example, if the gas tank 30 has analuminum liner, the filling flow rate is higher than the gas tank 30having a resin liner for the same tank pressure, tank temperature andpre-cooler temperature. Thus, the gas tank 30 having a higher heatradiation performance can be filled in a shorter time.

In step S3, the controller 46 of the vehicle 3 transmits the informationabout the filling flow rate determined in step S2 to the controller 24of the hydrogen station 2 by communication between the communicationdevice 44 and the communication device 21. In the following step S4, thecontroller 24 controls the hydrogen station 2 to achieve thecommunicated filling flow rate. More specifically, the controller 24adjusts the valve position of the flow rate control valve 16 to achievethe communicated filling flow rate with reference to the measurementresult of the flowmeter 17. As a result, the gas tank 30 is filled withhydrogen gas at a filling flow rate suitable for the current conditionsof the tank pressure, the tank temperature and the pre-coolertemperature and the characteristics concerning the gas tank 30.

During the filling, at least one of the display device 22 of thehydrogen station 2 and the display device 48 of the vehicle 3 providesan indication that filling is being performed at the filling flow ratedetermined in step S2. In other words, the person who performs fillingcan confirm that the filling flow rate is selected and controlled basedon various conditions including the pre-cooler temperature through theindication provided by at least one of the display devices 22 and 48 ofthe gas filling system 1.

Then, when the gas tank 30 is filled with a predetermined amount (anamount specified by the person who performs filling or a full fillingamount) of hydrogen gas, supply of hydrogen gas from the hydrogenstation 2 is stopped, and the filling is ended (step S5). Alternatively,at least one of the display devices 22 and 48 may provide the indicationdescribed above, such as an indication that the filling flow rate iscontrolled based on various conditions including the pre-coolertemperature, after the filling is ended or only after the filling isended.

After the filling is ended, the storage section (the RAM describedabove, for example) of at least one of the controllers 24 and 46 in thegas filling system 1 preferably temporarily stores thetransmission/reception history for the communication devices 44 and 21.For example, the transmission/reception history preferably includes ahistory of transmission of the pre-cooler temperature from thecommunication device 21 to the communication device 44 after the startof filling in step S1 or a history of transmission of information on thedetermined filling flow rate from the communication device 44 to thecommunication device 21 in step S3. Both the hydrogen station 2 and thevehicle 3 can retain the transmission/reception history. However, thetransmission/reception history is particularly preferably retained inthe vehicle 3. This is because it can be easily confirmed in automobilesafety inspection whether or not filling has been performed according tothe process shown in FIG. 3. In other words, if thetransmission/reception history is retained only by the hydrogen station2, the transmission/reception history concerning filling of a particularvehicle 3 has to be retrieved from various hydrogen stations 2 atdifferent sites, and this is a troublesome task.

Advantages of the gas filling system 1 according to this embodimentdescribed above will be described.

First, since the filling flow rate is determined based on the detectedpre-cooler temperature, an optimum filling flow rate suitable for thecooling capability of the pre-cooler 18 can be determined. For example,as described above, when the pre-cooler temperature is relatively high,the filling flow rate can be relatively low. Thus, smooth and quickfilling can be achieved while preventing the temperature in the gas tank30 from exceeding the upper limit temperature. In other words, even ifthe pre-cooler 18 fails to adequately cool hydrogen gas, filling doesnot need to be suspended or stopped, so that the person who performsfilling or the driver of the vehicle does not need to wait. On the otherhand, when the pre-cooler temperature is relatively low, the fillingflow rate can be relatively high. Thus, smooth and quick filling can beachieved in a shorter time while preventing the temperature in the gastank 30 from exceeding the upper limit temperature.

Furthermore, the filling flow rate is determined based on actualinformation about the internal environment of the gas tank 30, that is,the actually measured tank pressure and tank temperature, a moresuitable filling flow rate can be determined than in the case wherethese values are estimated. In other embodiments, the filling flow ratemay be determined and controlled without taking into account either orboth of the tank pressure and the tank temperature.

Furthermore, since the filling flow rate is determined based on thecharacteristics concerning the gas tank 30 (the heat radiationperformance, for example), the optimum filling flow rate suitable forthe gas tank 30 of the vehicle 3 can be determined. For example, if thegas tank 30 of the vehicle 3 has a relatively high heat radiationperformance, a relatively high filling flow rate can be determined.Thus, smooth filling can be performed in a shorter time while preventingthe temperature in the gas tank 30 from exceeding the upper limittemperature.

As described above, according to the preferred aspect of thisembodiment, the optimum filling flow rate can be determined based on thetemperature of the gas supplied from the gas station 2 to the gas tank30 (the pre-cooler temperature) and the characteristics and the internalconditions (the tank pressure and the tank temperature) of the gas tank30 to be filled. Therefore, the gas tank 30 can be filled with apredetermined amount of gas in the shortest possible time by the optimumfilling method.

In addition, the filling flow rate is primarily determined by thevehicle 3 rather than the hydrogen station 2. In the case where thehydrogen station 2 primarily determines the filling flow rate unlike inthis embodiment, the hydrogen station 2 can keep track of thecharacteristics concerning the gas tank 30 only to a limited extent. Forexample, even when a vehicle has its gas tank having a high temperaturerise rate replaced with a new gas tank having a low temperature riserate, the hydrogen station 2 determines the filling flow rate based onthe filling flow rate map designed for the old gas tank having a hightemperature rise rate. As a result, the filling time cannot be reduced.

To the contrary, according to this embodiment, since the vehicle 3determines the filling flow rate, the filling flow rate can bedetermined from the filling flow rate map Ma designed for the gas tank30 of the vehicle 3 without being affected by other vehicles. Thus, theoptimum filling flow rate reflecting the characteristics concerning thegas tank 30 can be determined. Therefore, filling can be performed inthe optimum manner for the gas tank 30 and therefore the vehicle 3without losing the benefit of the technical advances of the gas tank 30or the like. As for the hydrogen station 2, there is an advantage thatthe software of the filling flow rate map in the hydrogen station 2 doesnot need to be replaced for each new vehicle.

The vehicle 3 transmits data about he determined filling flow rate tothe hydrogen station 2. Therefore, the filling flow rate determined bythe vehicle 3 does not need to be manually input to the hydrogen station2. Furthermore, since the transmission/reception history is stored, itcan be checked in vehicle safety inspection or the like whether or notfilling has been performed at the optimum filling flow rate describedabove.

Furthermore, according to this embodiment, since the pre-coolertemperature is detected at the start of filling, the cooling capabilityof the pre cooler 18 can be determined at the start of filling. However,according to other embodiments, the pre-cooler temperature may bedetected during filling. In this case, the presence or absence of anabnormality of the pre-cooler 18 can be detected during filling.Furthermore, in the case where the pre-cooler temperature is detectedduring filling, the controller 46 of the vehicle 3 can select ordetermine again the filling flow rate suitable for the detectedpre-cooler temperature by referring to the filling flow rate map Ma.Thus, the hydrogen station 2 can change the filling flow rate to besuitable for the pre-cooler temperature during filling.

Modifications

Next, several modifications of the gas filling system 1 according tothis embodiment will be described. The modifications can be applied tothis embodiment singly or in combination.

According to a first modification, the tank pressure and the tanktemperature can be estimated so as to determine the filling flow rate.In this case, the tank pressure and the tank temperature can beestimated using a device of the hydrogen station 2. For example, thetank pressure can be estimated from the result detected immediatelyafter the start of filling by a pressure sensor provided in the gas flowchannel 13 of the hydrogen station 2. The tank temperature can beestimated from the result of detection by the outside air temperaturesensor 23.

According to a second modification, the position of the temperaturesensor T for detecting the pre-cooler temperature can be changed. Sinceit is essential only that the temperature sensor T can detect thetemperature of the hydrogen gas between the pre-cooler 18 and theupstream of the gas tank 30, the temperature sensor T can be provided onthe filling nozzle 12. Alternatively, the temperature sensor T can beprovided on the receptacle 32 or filling pipe 34 of the vehicle 3 todetect the temperature of the hydrogen gas discharged from the hydrogenstation 2 to the gas tank 3.

According to a third modification, a plurality of gas tanks 30 can beprovided. In the case where the vehicle 3 has a plurality of gas tanks,the gas tanks have different heat radiation performances depending onthe positions thereof and discharge different amounts of gas dependingon the way of supply to the fuel cell. Thus, in the case where thevehicle has a plurality of gas tanks 30, the filling flow rate can bedetermined from the filling flow rate map Ma based on the information(tank temperature and tank pressure) about the gas tank having thehighest tank temperature or the gas tank having the lowest gas pressureof the plurality of gas tanks. In this case, all the gas tanks can befilled with a predetermined amount of gas in a short time whilepreventing the tank temperature in the gas tanks from reaching the upperlimit temperature.

In the third modification, the tank temperature and the tank pressure ofthe gas tanks may be measured by the temperature sensor 40 and thepressure sensor 42 provided for each gas tank or measured by a singletemperature sensor 40 and a single pressure sensor 42 provided for allthe gas tanks. Alternatively, as described with regard to the secondmodification, the tank temperature and the tank pressure of the gastanks may be estimated.

INDUSTRIAL APPLICABILITY

The gas filling system 1 according to the present invention can beapplied to not only hydrogen gas but also any other gases whosetemperature rises during filling. Furthermore, the gas filling system 1according to the present invention can be applied to not only thevehicle 3 but also any other mobile bodies having a gas tank capable ofbeing externally filled with gas, such as an aircraft, a ship and arobot.

REFERENCE SIGNS LIST

-   1 gas filling system-   2 hydrogen station (gas station)-   3 vehicle (fuel cell vehicle)-   16 flow rate control valve (flow rate controlling device)-   18 pre-cooler-   21 communication device (first communication device)-   22 display device-   24 controller (second controller)-   30 gas tank-   40 temperature sensor-   42 pressure sensor-   44 communication device (second communication device)-   46 controller (first controller)-   48 display device-   T temperature sensor-   Ma filling flow rate map

1. A gas filling system comprising a vehicle having a gas tank; and agas station having a cooling device that cools a gas from a gas supplysource, the gas station discharging the gas cooled by the cooling deviceto fill said gas tank with the gas, the gas filling system furthercomprising: a temperature sensor that detects the temperature of the gascooled by said cooling device on the upstream side of said gas tank; anda first controller that is provided in said vehicle and determines thefilling flow rate of the gas to said gas tank based on the gastemperature detected by said temperature sensor.
 2. The gas fillingsystem according to claim 1, wherein said first controller has a map ofthe filling flow rate for each gas temperature to be detected by saidtemperature sensor and selects the filling flow rate from the map basedon the gas temperature detected by said temperature sensor.
 3. The gasfilling system according to claim 1, wherein said first controllerdetermines the filling flow rate based on characteristics concerningsaid gas tank.
 4. The gas filling system according to claim 1, whereinsaid temperature sensor detects said gas temperature at the start offilling.
 5. The gas filling system according to claim 1, wherein saidtemperature sensor detects said gas temperature during filling.
 6. Thegas filling system according to claim 1, wherein said vehicle has afirst communication device connected to said first controller, and saidgas station has: a flow rate controlling device; a second communicationdevice that receives information about said determined filling flow ratefrom said first communication device; and a second controller thatcontrols said flow rate controlling device to achieve the filling flowrate received by said second communication device.
 7. The gas fillingsystem according to claim 6, wherein said temperature sensor detects thegas temperature at said cooling device.
 8. The gas filling systemaccording to claim 7, wherein said temperature sensor detects said gastemperature at the start of filling or during filling.
 9. The gasfilling system according to claim 6, wherein at least one of said firstcontroller and said second controller stores a transmission/receptionhistory between said first communication device and said secondcommunication device.
 10. The gas filling system according to claim 9,wherein said transmission/reception history includes a history oftransmission of the information about said determined filling flow ratefrom said first communication device to said second communicationdevice.
 11. The gas filling system according to claim 6, wherein saidfirst controller determines the filling flow rate based oncharacteristics concerning said gas tank.
 12. The gas filling systemaccording to claim 6, wherein said first controller has a map of thefilling flow rate for each gas temperature to be detected by saidtemperature sensor and selects the filling flow rate from the map basedon the gas temperature detected by said temperature sensor.
 13. The gasfilling system according to claim 6, further comprising: a displaydevice that provides an indication that said filling flow rate is beingcontrolled or has been controlled based on the gas temperature detectedby said temperature sensor.
 14. The gas filling system according toclaim 1, wherein said first controller determines a lower filling flowrate when said temperature sensor detects a higher gas temperature thanwhen said temperature sensor detects a lower gas temperature.
 15. Thegas filling system according to claim 1, further comprising: a sensorthat obtains information about the interior of said gas tank, whereinsaid first controller determines the ling flow rate based on theinformation obtained by said sensor.
 16. The gas filling systemaccording to claim 15, wherein said sensor includes at least one of atemperature sensor and a pressure sensor.
 17. The gas filling systemaccording to claim 6, wherein said first controller determines a lowerfilling flow rate when said temperature sensor detects a higher gastemperature than when said temperature sensor detects a lower gastemperature.
 18. The gas filling system according to claim 6, furthercomprising: a sensor that obtains information about the interior of saidgas tank, wherein said first controller determines the filling flow ratebased on the information obtained by said sensor.
 19. The gas fillingsystem according to claim 18, wherein said sensor includes at least oneof a temperature sensor and a pressure sensor.